Neck rests on the seat back rests of vehicles have usually two parallel spaced rods of the neck rest, which are accommodated in sleeve arrangements for the neck rest, which are fixed on the frame of the back rest. The neck rest rods are often bent in a U-shape. The bridge of the U-shaped portion is located inside of the neck rest.
Known sleeve arrangements for neck rests have a head portion and a shank portion. The shank portion has a through going axial passage in which a rod of the neck rest is accommodated. The head portion is equipped with a locking means, which co-operates with grooves, a toothing or the like in a rod of the neck rest. Through this, it is possible to arrest the neck rest on a predetermined height or to change the desired height of the neck rest, respectively. Further, it is known to realise the head portion and the shank portion into a one-piece sleeve body made of plastic material.
The sleeve body or the sleeve shank, respectively, is fixed in a frame of the back rest of the seat. Through this, the arrangement of the sleeve arrangement for the neck rest is dependent from tolerances. The sleeve arrangement for the neck rest, on its part, is subject to tolerances when it is manufactured. In the U-shaped rods of the neck rest, a tolerance has also to be expected. The distance of the rods for the neck rest is not exactly always the same. If it does not correspond to the distance of the axes of the installed sleeve arrangement for the neck rest, the rods of the neck rest have to be bent somewhat, either apart from each other or towards each other. However, by doing so they are no more exactly parallel. In order to compensate the individual tolerances, the accommodation of the rod of a neck rest in a sleeve arrangement for the neck rest has to admit variances. However, through this there is the danger that noise is generated in the sleeve arrangements for the neck rest during driving by a vibration of the neck rest or the rods of the neck rest, respectively, which is unpleasant for the user of the seat, particularly as it is generated in the region of the ears of the user of the seat. In this context, it has already become known to pre-stress the neck rest rods inside the sleeve arrangement for the neck rest by springs, in order to regulate the sliding movement of the neck rest rod in the interior of the sleeve arrangement for the neck rest on the one hand, and to dampen the described noise on the other hand. However, with the known means, damping of the noise can only be achieved in an insufficient manner.